Dropbox lets you save your files 'in-the-cloud', which basically means that you save them to a remote location other than your local computer. This means that they are safely backed up somewhere else, can easily be shared with others, and can also be accessed from any location where you can get internet access.
Web Tools & Utilities
A language translation tool from Google. You can use it to translate text, webpages and documents. The selection of languages available for translation is extensive.
In addition to the standard translation tool, there are features like the 'Translated Search' option which allows you to search websites in other languages.
Free online image editor by Autodesk. It includes many of the image manipulation tools and features that you'd find on dedicated software like Photoshop. The list of features is extensive, but includes things cropping, hue & saturation, exposure adjustment, photographic filters & effects, cloning tools... It can be used on PC's, and an app is available for smartphones and tablets.
Music search engine for locating mp3 downloads. Beemp3 doesn't actually host mp3 files, but you can search for songs and it provides links to places where the mp3 can be downloaded.
Free antivirus and antispyware protection for Windows. This hugely popular antivirus and antispyware software can be easily downloaded, installed and kept up-to-date with the latest threats. In addition to AVG Free there are some additional paid-for features, but the free offering will provide enough protection for the average user.
Create MP3 audio files from YouTube videos. Just enter a YouTube URL and download the MP3.
Test your internet connection bandwidth to locations around the world with this interactive broadband speed test with great interactive interface.
Search torrents and download music, movies, games, software and much more. The Pirate Bay is one of the world's largest bittorrent trackers.
Need online storage to share or back-up large files? Offers free upload, download and storage as well as paid for premium accounts.
Basic photo-editing tools that you can use from inside your browser (there's no application to download). Also works inside Facebook, Flickr and Picasa Web albums.